Autoradiographic Visualization of G Protein-Coupled Receptors in Brain

Abstract

In this chapter, two in vitro techniques applied to study the anatomical localization of a receptor are revised: firstly, the receptor binding assay in sections, a technique to assess the location and distribution of a receptor in the tissue (descriptive and anatomical information), and, secondly, the [³⁵S]GTPγS-binding assay also in tissue slices, which allows the quantification of the level of G protein activation by a specific GPCR’s agonist. The latter technique provides additional information about the coupling efficacy of a receptor to G proteins (functional autoradiography), thus enabling the study of the first step in the intracellular signaling pathway after the receptor activation. Both techniques are basically performed for the in vitro autoradiographic visualization of receptors in tissue slices obtained from animal or human postmortem samples.